The goal of this study is to evaluate the incidence of Vitamin D deficiency in adults over the age of 65 years. This will be accomplished by having volunteers come to the General Clinical Research Center to fill out a questionnaire about their eating habits relating to calcium and vitamin D intake, and their habits regarding outdoor activities and exposure to sunlight. After completing the questionnaire, a 15-ml blood sample will be obtained from each volunteer to measure circulating concentrations of 25-hydroxyvitamin D, which is a measure to vitamin D status.